Field of the Invention
The present invention relates to printing paper for an industrial inkjet printing press to be used in an industrial rotary inkjet printing press and to a method for producing a printed material that uses that printing paper for an industrial inkjet printing press.
Description of Related Art
A rotary type of industrial inkjet printing press that uses an inkjet recording system is known as an industrial or commercial printing press for producing large quantities of commercial printed material or newspapers (see, for example, Patent Document 1). Industrial rotary inkjet printing presses are sold under the names of, for example, the Truepress Jet manufactured by Dainippon Screen Mfg. Co., Ltd., the MJP Series manufactured by Miyakoshi Printing Machinery, Co., Ltd., Prosper and Versamark manufactured by the Eastman Kodak Co , Inkjet Web Press manufactured by the Hewlett-Packard Co., and JetLeader manufactured by Tokyo Kikai Seisakusho, Ltd.
Although dependent on various printing conditions, these industrial rotary inkjet printing presses have color printing speeds of 60 m/min or more that are more than ten times faster than ordinary, home-use inkjet printers, small-office/ home-office (SOHO) inkjet printers and large-format inkjet printers. These printing presses demonstrate particularly high newspaper printing speeds, with industrial rotary inkjet printing presses for newspaper applications demonstrating printing speeds of greater than 100 m/min within the range of 150 m/min to 200 m/min. Consequently, industrial rotary inkjet printing presses are distinguished from ordinary, home-use inkjet printers, SOHO inkjet printers and large-format inkjet printers.
Industrial rotary inkjet printing presses are able to accommodate on-demand printing since they are capable of handling variable information. There are many cases in which printing companies employ a system in which fixed information is printed with a conventional printing press such as an offset rotary printing press, while variable information is printed with an industrial rotary inkjet printing press. Offset rotary printing presses are used particularly frequently for conventional printing presses from the viewpoints of printing quality and production cost.
Thus, it is necessary to have printability for both printing by a conventional printing press such as an offset rotary printing press and printing by an industrial rotary inkjet printing press. Unless printability for both of these types of printing is provided, printed material having adequate image quality as a commercial product cannot be produced by these printing presses.
Coated paper for inkjet printing is known for use as coated paper for inkjet printing that has high white paper glossiness, superior ink absorbency, ink fixability and coated layer strength and allows the obtaining of high-quality printed material using a commercial inkjet printing press, the coated paper for inkjet printing having a coated layer containing pigment and binder on at least one side of a base paper, wherein the pigment contains 70% by weight or more of acicular precipitated calcium carbonate, the binder contains a latex binder and starch, the ratio of the weight of the latex binder to the weight of the starch (weight of latex binder/weight of starch) is 0.3 to 25, and the ratio of the weight of the pigment to the weight of the binder in the coating layer (ratio of weight of pigment/weight of binder) is 3 to 30 (see, for example, Patent Document 2).
Newsprint paper for inkjet-compatible offset printing is known for use as newsprint paper for inkjet-compatible offset printing that has printability with a newspaper offset rotary press while also having superior inkjet printability, the newsprint paper for inkjet-compatible offset printing containing primarily waste paper pulp for the pulp raw material of the base paper, containing white carbon for the filler, is made without an internal sizing agent, and is subjected to sizing with a surface sizing agent, wherein (a) the fiber composition of defibrated pulp is such that the amount of needle bleached kraft pulp is 15% by weight or less, (b) the length-average fiber length of the defibrated pulp is 0.7 mm to 1.0 mm, (c) the length-average fiber length distribution of the defibrated pulp is such that pulp having a length-average fiber length of 1.2 mm or more accounts for 20% or less of the defibrated pulp, (d) the newsprint paper is coated with a surface treatment agent containing a surface sizing agent and a binder and the water absorption time thereof is 50 seconds to 170 seconds, and (e) the shape factor resulting from inkjet printing as determined using a specific measurement method is 100 to 200 (see, for example, Patent Document 3).